Robert Tienwen Chien (November 20, 1931 – December 8, 1983) was an American computer scientist concerned largely with research in information theory, fault-tolerance, and artificial intelligence (AI), director of the Coordinated Science Laboratory (CSL) at the University of Illinois at Urbana–Champaign, and known for his invention of the Chien search and seminal contributions to the PMC model in system level fault diagnosis.